Through-Wall Imaging With UWB Radar System - KEMT FEI TUKE

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4.1 Through-Wall TOA Estimation 54 a) b) Fig. 4.1.9: SAR measurement. a) Radar system in front of the wall. b) Measured object behind the wall. Z �rw= 4 4 m Room Antennas movement 0.5 m 1 m 2 m 0.5 m 1 m 5 m Metal plate 0.2 m Fig. 4.1.10: SAR measurement - Scenario 1. was 0.45 m vertically. The antenna system was moved in parallel to the wall along 2 m at distance 0.5 m from the wall. The object was placed 1 m behind the wall inside the room (Fig. 4.1.10). A metal plate of size 1 m × 0.5 m and thickness of a few millimeters was chosen as an object behind the wall. In Fig. 4.1.11 a) and Fig. 4.1.11 b), the migrated images with conventional method where TOA si computed by (4.1.8) and the proposed method of T OA computation by (4.1.1) are shown, respectively. The targets have marked distances from antennas at antennas position 1 m in the scanning direction. The position of the metal plate in Z direction in Fig. 4.1.11 a) is about 1.9 m, what is approximately 0.2 m deviation from the real position. In Fig. 4.1.11 b) it is about 1.7 m what is very close to the real position. The front wall is in both images in the correct position, it starts approximately at 0.5 m in Z direction. The rear X
4.1 Through-Wall TOA Estimation 55 X[m] Front wall 1.9 m Metal plate 4.9 m Rear wall Z[m] X[m] Front wall 1.7 m Metal plate 4.7 m a) b) Rear wall Fig. 4.1.11: Migrated images - Scenario 1. a) Conventional method without wall compensation. b) Proposed method with precise TOA estimation. wall is in the correct position only in Fig. 4.1.11 b), approximately at 4.7 m in Z direction, in Fig. 4.1.11 a) it starts at 4.9 m. Scenario 2 demonstrates how important true T OA estimation is in case the objects are not in parallel with the scanning direction. The wall compensation can be done also in much simpler way. An additional delay for a wave penetrating perpendicularly to the wall can be computed by (2.5.8) as we described in Section 2.5.3 and used for wall compensation [86]. This approach could be used only in case the waves are penetrating perpendicularly to the wall, what is not fulfilled in praxis. Compensation by this simple approach still provides much better results than without compensating the wall at all. However, it is not as precise as the compensation by the proposed method, as is shown in this second scenario (Fig. 4.1.12). The metal plate of size 0.67 m × 0.75 m was placed aslant behind the 0.4 m thick brick wall with relative permittivity approximately εrw = 3.4. As it can be seen in Fig. 4.1.13, even if the waves penetrate aslant in the wall, the proposed method provides correct coordinations of the left-bottom metal plate corner [X = 1.6 m, Z = 1 m], unlike the simple method for compensation [X = 1.73 m, Z = 1 m]. A noncompensation of the wall will cause that the objects will not be imaged in correct position. The image will be unfocused as well [141], however, in real measurements only the shifting of the objects to the incorrect positions is evident. Z[m]
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TECHNICAL UNIVERSITY OF KOˇSICE Fa
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Acknowledgement I give a sincere gr
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CONTENTS v 3 Goals of Dissertation
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LIST OF FIGURES vii List of Figures
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LIST OF FIGURES ix 4.4.3 Aquarium f
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LIST OF FIGURES xi List of Symbols
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LIST OF FIGURES xiii kx - Horizonta
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Chapter 1 Introduction 1.1 Motivati
Page 17 and 18: 1.3 Thesis Organization 3 In additi
Page 19 and 20: Chapter 2 State Of The Art 2.1 UWB
Page 21 and 22: 2.2 Through-Wall Radar Basic Model
Page 23 and 24: 2.3 SAR Scanning 9 and shall remain
Page 25 and 26: 2.4 Calibration and Preprocessing 1
Page 27 and 28: 2.4 Calibration and Preprocessing 1
Page 29 and 30: 2.5 Radar Imaging Methods Overview
Page 55 and 56: Chapter 4 Selected Research Methods
Page 57 and 58: 4.1 Through-Wall TOA Estimation 43
Page 67: 4.1 Through-Wall TOA Estimation 53
Page 71 and 72: 4.2 Measurements of the Wall Parame
Page 81 and 82: 4.3 Highlighting of a Building Cont
Page 91 and 92: 4.4 Measurements of the Practical S
Page 99 and 100: 5.1 Conclusion and Future Work 85 5
Page 101 and 102: 50 100 150 200 250 300 350 400 Z 45
Page 103 and 104: 50 100 150 200 250 300 350 400 Z 45
Page 105 and 106: 50 100 150 200 250 300 350 400 Z 45
Page 107 and 108: 50 100 150 200 250 300 350 400 Z 45
Page 109 and 110: Z [cm] Z [cm] 50 100 150 200 250 30
Page 111 and 112: Z [cm] 50 100 150 200 250 300 b) Em
Page 113 and 114: BIBLIOGRAPHY 99 [13] T. W. Barrett,
Page 115 and 116: BIBLIOGRAPHY 101 [46] G. Derveaux,
Page 117 and 118: BIBLIOGRAPHY 103 [81] S. Kidera, T.
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BIBLIOGRAPHY 105 [115] J. Sachs, M.
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BIBLIOGRAPHY 107 [150] O. Yilmaz, S
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Through-Wall Imaging With UWB Radar System - KEMT FEI TUKE

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